Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.1 (NADPH-diaphorase)
 3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite the wealth of literature concerned with muscle fiber biochemical, ultrastructural and physiological characteristics, little information is available regarding the metabolic enzyme activities of alpha-motoneurons. The present study examines the metabolism of alpha-motoneurons located in the lateral cell column of the rat lumbosacral enlargment with a quantitative histochemical technique. Variation in the activities of alpha-glucan phosphorylase, NADH-diaphorase, succinic dehydrogenase and acid phosphatase were detectable with the photographic densitometry and atomic absorption spectrophotometry technique. No difference in the glycolytic enzyme activity (mitochondrial alpha-glycerophosphate dehydrogenase) was observed. Analysis of lactate dehydrogenase isoenzymes demonstrated the existence of H type isoenzyme in alpha-motoneurons, consistent with other observations indicating predominance of aerobic metabolism within these neurons. The activities of the former enzymes in alpha-motoneurons formed a complete spectrum of activities, distributed unimodally. Smaller motoneurons exhibited the greatest NADH-D and acid phosphatase activities; phosphorylase activity was greatest in larger motoneurons. Significant variation in the enzyme activity of similar-sized motoneurons suggests that the metabolism of the motoneuron is regulated by factors other than cell size. Relationships between motoneuron metabolic enzyme activity and motor unit type are under current investigation.
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PMID:Metabolic variation among rat lumbosacral alpha-motoneurons. 668 5

To determine the effect of a soft diet and aging on the masticatory motor unit, we investigated the morphologic and metabolic properties of the superficial masseter muscle and its motoneurons in rats. Twenty rats were divided into four groups of five rats: rats fed a hard diet until 4 months after birth (hard, young), rats fed a soft diet until 4 months after birth (soft, young), rats fed a hard diet until 22 months after birth (hard, old), and rats fed a soft diet until 22 months after birth (soft, old). The diameter of the fast-twitch oxidative glycolytic muscle fiber was significantly smaller in the soft than the hard, and in the old than the young groups. The glycolytic enzyme (phosphofructokinase) activity of the muscle was significantly weaker in the old than the young group. There was no significant difference in soma diameter of the motoneurons between the soft and hard group, while the diameter was significantly larger in the old than in the young group. There was no significant difference in NADH-diaphorase activity of the motoneurons between the soft and hard group, while significantly less activity was demonstrated in the old than in the young group. The reduction in motor unit activity caused by the soft diet is considered to influence the morphologic and metabolic properties in the superficial masseter muscle but not in its motoneurons. The reduction in the oxidative enzyme activity of motoneurons with aging may occur regardless of the reduction in motor unit activity.
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PMID:Effect of soft diet and aging on rat masseter muscle and its motoneuron. 829 95

Polyglutamine-containing proteins expressed in the CAG repeat diseases Huntington's disease and dentatorubralpallidoluyisian atrophy have recently been suggested to inhibit the key glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). To examine the consequences of GAPDH inhibition upon neuronal survival, we exposed murine neocortical cell cultures to the inhibitor of GAPDH and triosephosphate isomerase, alpha-monochlorohydrin. Cultures exposed to 6-15 mM alpha-monochlorohydrin for 48 h exhibited an increase in dihydroxyacetone phosphate and a decrease in neuronal ATP that was followed by progressive neuronal death; some glial death occurred at high drug concentrations. The neuronal death was characterized by cell body shrinkage and chromatin condensation and was sensitive to cycloheximide and to the caspase inhibitors Z-Val-Ala-Asp fluoromethylketone and tert-butoxycarbonyl-Asp fluoromethylketone. Neurons in striatal cell cultures were more vulnerable to death induced by exposure to alpha-monochlorohydrin, except that NADPH-diaphorase(+) neurons were selectively spared. Repeated addition of the glycolytic endpoint metabolite pyruvate to the bathing medium attenuated both the drop in neuronal ATP and the neuronal cell death.
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PMID:Neuronal death in cultured murine cortical cells is induced by inhibition of GAPDH and triosephosphate isomerase. 970 87

Null mutations in the structural gene encoding phosphoglucose isomerase completely abolish activity of this glycolytic enzyme in Kluyveromyces lactis and Saccharomyces cerevisiae. In S. cerevisiae, the pgi1 null mutation abolishes growth on glucose, whereas K.lactis rag2 null mutants still grow on glucose. It has been proposed that, in the latter case, growth on glucose is made possible by an ability of K. lactis mitochondria to oxidize cytosolic NADPH. This would allow for a re-routing of glucose dissimilation via the pentose-phosphate pathway. Consistent with this hypothesis, mitochondria of S. cerevisiae cannot oxidize NADPH. In the present study, the ability of K. lactis mitochondria to oxidize cytosolic NADPH was experimentally investigated. Respiration-competent mitochondria were isolated from aerobic, glucose-limited chemostat cultures of the wild-type K. lactis strain CBS 2359 and from an isogenic rag2Delta strain. Oxygen-uptake experiments confirmed the presence of a mitochondrial NADPH dehydrogenase in K.lactis. This activity was ca. 2.5-fold higher in the rag2Delta mutant than in the wild-type strain. In contrast to mitochondria from wild-type K. lactis, mitochondria from the rag2Delta mutant exhibited high rates of ethanol-dependent oxygen uptake. Subcellular fractionation studies demonstrated that, in the rag2Delta mutant, a mitochondrial alcohol dehydrogenase was present and that activity of a cytosolic NADPH-dependent 'acetaldehyde reductase' was also increased. These observations indicate that two mechanisms may participate in mitochondrial oxidation of cytosolic NADPH by K. lactis mitochondria: (a) direct oxidation of cytosolic NADPH by a mitochondrial NADPH dehydrogenase; and (b) a two-compartment transhydrogenase cycle involving NADP(+)- and NAD(+)-dependent alcohol dehydrogenases.
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PMID:Two mechanisms for oxidation of cytosolic NADPH by Kluyveromyces lactis mitochondria. 1211 36